The general syntax of the grep commands is: You can use fgrep to find all the lines of a file that contain a particular word. For example, to list all the lines of a file named myfile in the current directory that contain the word dog, enter at the Unix prompt:
Outer core. The outer core of the Earth is a liquid layer about 2,300 km (1,400 mi) thick and composed of iron and nickel that lies above Earth's solid inner core and below its mantle.Its outer boundary lies 2,890 km (1,800 mi) beneath Earth's surface.ecause of its high temperature, modeling work has shown that the outer core is a low viscosity fluid (about ten times the viscosity of liquid metals at the surface) that convects turbulently. Eddy currents in the nickel iron fluid of the outer core are believed to influence the Earth's magnetic field.
The inner core which is at the very centre of the Earth is a solid layer approximately 780 miles (1,250 km) thick. The core is at a very high temperature and so the outer core is always molten, however as the depth within the core increase the pressure drives the melting temperature up above the in-situ temperatures even though they reach 6700ÃÂºF (3700ÃÂºC).